[PATCH v3 6/9] powerpc/kuap: Use MMU_FTR_KUAP on all and refactor disabling kuap
From: Christophe Leroy
Date: Tue Jul 11 2023 - 11:59:57 EST
All but book3s/64 use a static branch key for disabling kuap.
book3s/64 uses an mmu feature.
Refactor all targets to use MMU_FTR_KUAP like book3s/64.
For PPC32 that implies updating mmu features fixups once KUAP
has been initialised.
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
arch/powerpc/include/asm/book3s/32/kup.h | 9 ---------
arch/powerpc/include/asm/book3s/64/kup.h | 5 -----
arch/powerpc/include/asm/kup.h | 11 +++++++++++
arch/powerpc/include/asm/nohash/32/kup-8xx.h | 9 ---------
arch/powerpc/include/asm/nohash/kup-booke.h | 8 --------
arch/powerpc/kernel/cputable.c | 4 ++++
arch/powerpc/mm/book3s32/kuap.c | 5 +----
arch/powerpc/mm/init_32.c | 2 ++
arch/powerpc/mm/nohash/kup.c | 6 +-----
9 files changed, 19 insertions(+), 40 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/32/kup.h b/arch/powerpc/include/asm/book3s/32/kup.h
index 0da0dea76c47..4ca6122ef0e1 100644
--- a/arch/powerpc/include/asm/book3s/32/kup.h
+++ b/arch/powerpc/include/asm/book3s/32/kup.h
@@ -9,10 +9,6 @@
#ifndef __ASSEMBLY__
-#include <linux/jump_label.h>
-
-extern struct static_key_false disable_kuap_key;
-
#ifdef CONFIG_PPC_KUAP
#include <linux/sched.h>
@@ -20,11 +16,6 @@ extern struct static_key_false disable_kuap_key;
#define KUAP_NONE (~0UL)
#define KUAP_ALL (~1UL)
-static __always_inline bool kuap_is_disabled(void)
-{
- return static_branch_unlikely(&disable_kuap_key);
-}
-
static inline void kuap_lock_one(unsigned long addr)
{
mtsr(mfsr(addr) | SR_KS, addr);
diff --git a/arch/powerpc/include/asm/book3s/64/kup.h b/arch/powerpc/include/asm/book3s/64/kup.h
index 72fc4263ed26..a014f4d9a2aa 100644
--- a/arch/powerpc/include/asm/book3s/64/kup.h
+++ b/arch/powerpc/include/asm/book3s/64/kup.h
@@ -230,11 +230,6 @@ static inline u64 current_thread_iamr(void)
#ifdef CONFIG_PPC_KUAP
-static __always_inline bool kuap_is_disabled(void)
-{
- return !mmu_has_feature(MMU_FTR_KUAP);
-}
-
static inline void kuap_user_restore(struct pt_regs *regs)
{
bool restore_amr = false, restore_iamr = false;
diff --git a/arch/powerpc/include/asm/kup.h b/arch/powerpc/include/asm/kup.h
index 24cde16c4fbe..bab161b609c1 100644
--- a/arch/powerpc/include/asm/kup.h
+++ b/arch/powerpc/include/asm/kup.h
@@ -6,6 +6,12 @@
#define KUAP_WRITE 2
#define KUAP_READ_WRITE (KUAP_READ | KUAP_WRITE)
+#ifndef __ASSEMBLY__
+#include <linux/types.h>
+
+static __always_inline bool kuap_is_disabled(void);
+#endif
+
#ifdef CONFIG_PPC_BOOK3S_64
#include <asm/book3s/64/kup.h>
#endif
@@ -41,6 +47,11 @@ void setup_kuep(bool disabled);
#ifdef CONFIG_PPC_KUAP
void setup_kuap(bool disabled);
+
+static __always_inline bool kuap_is_disabled(void)
+{
+ return !mmu_has_feature(MMU_FTR_KUAP);
+}
#else
static inline void setup_kuap(bool disabled) { }
diff --git a/arch/powerpc/include/asm/nohash/32/kup-8xx.h b/arch/powerpc/include/asm/nohash/32/kup-8xx.h
index a372cd822887..d0601859c45a 100644
--- a/arch/powerpc/include/asm/nohash/32/kup-8xx.h
+++ b/arch/powerpc/include/asm/nohash/32/kup-8xx.h
@@ -9,17 +9,8 @@
#ifndef __ASSEMBLY__
-#include <linux/jump_label.h>
-
#include <asm/reg.h>
-extern struct static_key_false disable_kuap_key;
-
-static __always_inline bool kuap_is_disabled(void)
-{
- return static_branch_unlikely(&disable_kuap_key);
-}
-
static inline void __kuap_save_and_lock(struct pt_regs *regs)
{
regs->kuap = mfspr(SPRN_MD_AP);
diff --git a/arch/powerpc/include/asm/nohash/kup-booke.h b/arch/powerpc/include/asm/nohash/kup-booke.h
index 71182cbe20c3..8e4734c8fef1 100644
--- a/arch/powerpc/include/asm/nohash/kup-booke.h
+++ b/arch/powerpc/include/asm/nohash/kup-booke.h
@@ -13,18 +13,10 @@
#else
-#include <linux/jump_label.h>
#include <linux/sched.h>
#include <asm/reg.h>
-extern struct static_key_false disable_kuap_key;
-
-static __always_inline bool kuap_is_disabled(void)
-{
- return static_branch_unlikely(&disable_kuap_key);
-}
-
static inline void __kuap_lock(void)
{
mtspr(SPRN_PID, 0);
diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
index 8a32bffefa5b..e97a0fd0ae90 100644
--- a/arch/powerpc/kernel/cputable.c
+++ b/arch/powerpc/kernel/cputable.c
@@ -75,6 +75,10 @@ static struct cpu_spec * __init setup_cpu_spec(unsigned long offset,
t->cpu_features |= old.cpu_features & CPU_FTR_PMAO_BUG;
}
+ /* Set kuap ON at startup, will be disabled later if cmdline has 'nosmap' */
+ if (IS_ENABLED(CONFIG_PPC_KUAP) && IS_ENABLED(CONFIG_PPC32))
+ t->mmu_features |= MMU_FTR_KUAP;
+
*PTRRELOC(&cur_cpu_spec) = &the_cpu_spec;
/*
diff --git a/arch/powerpc/mm/book3s32/kuap.c b/arch/powerpc/mm/book3s32/kuap.c
index 28676cabb005..24c1c686e6b9 100644
--- a/arch/powerpc/mm/book3s32/kuap.c
+++ b/arch/powerpc/mm/book3s32/kuap.c
@@ -3,9 +3,6 @@
#include <asm/kup.h>
#include <asm/smp.h>
-struct static_key_false disable_kuap_key;
-EXPORT_SYMBOL(disable_kuap_key);
-
void kuap_lock_all_ool(void)
{
kuap_lock_all();
@@ -30,7 +27,7 @@ void setup_kuap(bool disabled)
return;
if (disabled)
- static_branch_enable(&disable_kuap_key);
+ cur_cpu_spec->mmu_features &= ~MMU_FTR_KUAP;
else
pr_info("Activating Kernel Userspace Access Protection\n");
}
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index d4cc3749e621..d8adc452f431 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -126,6 +126,8 @@ void __init MMU_init(void)
setup_kup();
+ update_mmu_feature_fixups(MMU_FTR_KUAP);
+
/* Shortly after that, the entire linear mapping will be available */
memblock_set_current_limit(lowmem_end_addr);
}
diff --git a/arch/powerpc/mm/nohash/kup.c b/arch/powerpc/mm/nohash/kup.c
index 552becf90e97..94ff82b9ae60 100644
--- a/arch/powerpc/mm/nohash/kup.c
+++ b/arch/powerpc/mm/nohash/kup.c
@@ -5,7 +5,6 @@
#include <linux/export.h>
#include <linux/init.h>
-#include <linux/jump_label.h>
#include <linux/printk.h>
#include <linux/smp.h>
@@ -13,16 +12,13 @@
#include <asm/smp.h>
#ifdef CONFIG_PPC_KUAP
-struct static_key_false disable_kuap_key;
-EXPORT_SYMBOL(disable_kuap_key);
-
void setup_kuap(bool disabled)
{
if (disabled) {
if (IS_ENABLED(CONFIG_40x))
disable_kuep = true;
if (smp_processor_id() == boot_cpuid)
- static_branch_enable(&disable_kuap_key);
+ cur_cpu_spec->mmu_features &= ~MMU_FTR_KUAP;
return;
}
--
2.41.0